Inductor-alternator.



PATENTED SEPT. 18, 1906.

D. B. RUSHMORE. INDUGTOR ALTERNATOR.

PP I

K057765563: my 6050/. w, 2- .OdV/d d ffus/ymore PATENTED SEPT. 18, 1906.

D. B. RUSHMORE. INDUCTOR ALTERNATOR.

APPLICATION FILED OCT.5,1905.

2 SHEETS-SHBET 2.

II'IvIII lllfil'll' 9 Att'g.

I of a frequenc equal to UNITED STATES PATENT OFFICE.

DAVID B. RUSHMORE, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CCRPORATION OF NEW YORK.

lNDUCTOR-ALTERNATQR.

Specification of Letters Patent.

Patented Sept. 18, 1906.

Application filed October 5, 1905. Serial No. 281,408.

My invention relates to dynamo-electricmachines, and particularly refers'to inductor-alternators of the general type described in Patent No. 499,446, Stanley andKelly,

dated June 13, 1893. The type of alternator disclosed in this patent comprises a cylindrical revolving inductor with polar projections at both ends, an armature-body surrounding the inductor and carrying armature-coils in inductive relation to the polar projections, and a field-coil surrounding the inductor and supported at-the central portion of the armature-body between the armature-coils. A machine of-this type produces an alternating current in the armature-coils the'number of poles at each end 0 the inductor multiplied by the number of revolutions per second. The minimum number of poles that can be used in a machine of this type as heretofore ar ranged while maintaining a mechanical balance is two at each. end of the inductor.

Such a machine would give two cycles per revolution. For low-frequency alternators driven by. steam-turbines a speed would be required too low for eihcient operation of the turbine--particularly in units of comparatively small output.

The object of my invention is to reorganize an alternator of the type above described so that the maximum speed for a given frequency may be doubled.

In an application Serial No. 268,316, filed July 6, 1905, by C. A. Kelsey, assignor to the Stanley Electric Manufacturing Company, of Pittsfield, Massachusetts, is described an inductor-alternator in which the inductor is provided'with a helicalpolar rojection, so that only one cycle per revolution is obtained, while the machine is neverthelessv properly balanced.

My invention consists in rearranging an inductor-alternator of the type described in Patent No. 499,446, above referred to, so that .the inductor may be provided with helicar polar projections." In this way I obtain a bridge joining machine having the desirable characteristics of the alternator described in that patent, while at the same time securing a machine which will produce only one cycle per revolution.

My reference to whichv Figure 1 shows an end elevation of an inductoralternator arranged in accordance withv my invention. Fig. 2 shows a side elevation of the same, one-half of the armaturebody being removed; and Fig. shows a diae grammatic development of one-half of the armature.

' In the drawings, 1 represents the inductor,

mounted on the revolving shaft S. The ininvention will best be understood by the accompanying drawings, in

ductor is provided at each end with a helical as is clearly shown in Fig. 2, and

projection, these projections are preferably oppositely arranged-that is, if one helix is considered as right handed the other is left-handed. A

represents the armature-body, which is pro vided at each end with laminations a, so as to form a laminated ring surrounding each polar projection of the inductor, the two rings being joined by a bridge of magnetic material, F represents the field coil or coils, which are. supported by the armature-body beneath the magnetic bridge joining the two laminated rings. The armature-coils C C are arranged in helical slots in the laminated rings of the armature-body. The magnetic U the laminated rings is provid ed with ventilating-holes I'I.

71th this construction it is evident that the field-coils will magnetize the inductor, so that one helical projectionwill be of north polarity and the other of south polarity. A flux passes outwardly from one polar pro'ec' tion through the laminated ring surroun ing it, across the magnetic bridge to the other pole of the inductor. If the armature-coils are arranged in -inductive relation to the polar projections it is evident thatas the inductor revolves alternating electromotive forces will be induced in: the armature-coils,

laminated ring, and back to the other helical and since the projections are in the form of a helix the induced electromotive force in the armature-coils will pass through one cycle for each revolution 0 the inductor.

As has been pointed out heretofore, the

I helical polar proiections are preferably oppo ninety electrical degrees, by C.

sitely arranged. The purpose of this is to allow them to act more eflicient-ly as blowers,

drawing air in'from both ends of the machine;

This air passes between the field and armature coils, cooling both of them, and escapes outwardly through the holes H in the central portion of the arniature-bodyj Furthermore, since air is drawn in from both, ends toward the center the inductor is balanced with respect to the axial wind-pressure, so that there is no end thrust due to the blower action.

I the end connectionsof each coil extend substantially one hundred'and eightydegrees .around the'armat-ure. This is also clearly shown in Fig. 1. The machine is not limited to the production of two-phase currents but by properly arranging the coils currents of any. number of phases may be. secured, as will be obvious to those skilled in the art.

What I claim as new, and' desire to secure.

by Letters Patent of the United'States, is

' 1; In a dynamo-electric machine, a revolving inductor havin a helical polar proj ection at each end,- a field-coil surrounding the.in-. ductor between said projections, and a sta- -tionary armature provided with coils in in.

ductive relationto said projections.

2. In a dynamo electric machine, a revolvmg inductor having a helical polar'projection V ing inductor having a helical The machine is also balanced magmetically.

one phase are indicatedat each end, a field-coil surrounding the inductor between said projections, an armature-body surrounding said inductor, a'nd helically-arranged coils carried in slots in said armature-body opposite said polar projections;

3. In adynamo-electric machine, a revolvolar projection at each end, an armature-li'ody having a laminated ring surrounding each polar pro- 'ection and a magnetic. bridge joining said laminated rings, a field-coil surrounding the central portion of the inductor and su ported by the armature-body beneath sald magnetic bridge, and armature coils arranged in helical slots in said laminated rings.

4. In a dynamo-electric machine, a revolvinginductor having oppositely-arranged helical projections at its ends, a field-coil surrounding the inductor between said projections, an armature-body surrounding said inductor and provided with ventilatingeholcs near its central portion, and coilscarried by said armature-body in inductive relation to said polar ro ectlons,

.5. In a ynamoelectric machine, arevolv-.. inginductor having oppositely-arranged heli- .cal projections at its ends, an armature-body having a laminated. ring surrounding each olar rojection and a magnetic bridge joinmy; sald. laminated rings andprovided with.

ventilating-holes, a field-coil su ported by 'thearr'nature-body beneath said ridge, and -'armature-coils arranged in helical-slots in .said laminated rings. 4

In witness whereof. I have'hereunto set my hand this ab day of October, 1905.

' DAVID B, RUSHMORE. I

Witnesses: I I i BENJAMIN BpITI-U-LL, MARG RET E: WooLLnY. 

